Apparatus for detecting emergency venting of brake pipe

ABSTRACT

This invention relates to locomotive brake control apparatus operable responsively to a certain pressure differential developed by a chosen rate of flow of fluid under pressure from the main fluid pressure storage reservoir on the locomotive to a train brake pipe, resulting from an emergency rate of reduction of the pressure in the train brake pipe initiated at a location in the train remote from the locomotive as a result of a ruptured or separated brake pipe occurring while effecting a brake release subsequent to effecting a reduction of pressure in the train brake pipe that is in excess of the reduction required to obtain a full service brake application on the entire train, to cause closing of the brake pipe cut-off valve of the brake valve on the locomotive and thereby termination of the supply of fluid under pressure to the train brake pipe by this brake valve irrespective of the location in the train brake pipe at which the emergency rate of reduction in train brake pipe pressure originated.

United States Patent 1 [111 3,749,453

Wilson et al. July 31, 1973 APPARATUS FOR DETECTING EMERGENCY VENTING OFBRAKE PIPE 57 S R CT [75] Inventors: Richard wilsifnv Mqmoeville; Thisinvention relates to locomotive brake control ap- Robert-1' worbmsi bothof paratus operable responsively to a certain pressure dif ferentialdeveloped by a chosen rate of flow of fluid under pressure from the mainfluid pressure storage reservoir on the locomotive to a train brakepipe, re-

[73] Assignee: Westinghouse Air Brake Company, Wilmerding, Pa.

[22] Filed: 1972 sulting from an emergency rate of reduction of the [21]Appll 3 297 pressure in the train brake pipe initiated at a location inthe train remote from the locomotive as a result of 9 a ruptured orseparated brake pipe occurring while ef- [52] 0.8. CI. 303/67, 303/53fecting a brake release subsequent to effecting a reduc [51 Illt. Cl B6011/32 tion of pressure in the train brake p that is in excess [58] Fleld0f Search 303/53, 60, 67, 75, of the reduction required to obtain a nService brake 303/77 application on the entire train, to cause closingof the brake pipe cut-off valve of the brake valve on the locoisb]References Cited motive and thereby termination of the supply of fluidUNITED STATES PATENTS under pressure to the train brake pipe by thisbrake 3,525,556 8/1970 Ferguson 303/67 al sp t f th ati n in the trainrake pip 3.539226 1 1/1970 Barber 303/20 at which the emergency rate ofreduction in train brake pipe pressure originated.

Primary ExaminerDuane A. Reger Att0rneyRalph W. Mclntire, Jr. et al. 19Claims 4 Drawing Figures PAIENIED JUL3 1191a sum 2 or 2' APPARATUS FORDETECTING EMERGENCY VENTING OF BRAKE PIPE BACKGROUND OF THE INVENTIONThe brake control equipment on most locomotives presently in use onAmerican railroads embody a charging cut-off pilot valve device normallyoperable responsively to an emergency rate of reduction of pressure inthe train brake pipe to cause the supply of fluid under pressure to thebrake pipe cut-off valve of the brake valve on the locomotive whereuponthis cut-off valve is closed, thereby rendering the relay valve of thisbrake valve ineffective to supply fluid under pressure to the trainbrake pipe. Consequently, the brake control valve on the locomotive andeach car in the train thereupon operates in response to the emergencyrate of reduction of pressure occurring in the train brake pipe toeffect an emergency brake application on the respective vehicle in thetrain. Whenever an emergency rate of reduction of the pressure in thetrain brake pipe is initiated from a location remote from thelocomotive, the resulting reduction of pressure in that portion of thetrain brake pipe extending from end to end of the locomotive causes therelay valve of the brake valve on the locomotive to operate in responseto this reduction of pressure in this portion of the train brake pipe toeffect the supply of fluid under pressure from the main reservoir on thelocomotive to the train brake pipe via the brake pipe cut-off valve ofthis brake valve to compensate for this reduction of pressure in thetrain brake pipe. Therefore, it has been found that this supply of fluidunder pressure to the train brake pipe, while effecting an emergencyrate of reduction of pressure in the train brake pipe initiated at alocation in the train remote from the locomotive as a result of aruptured or separated brake pipe or the movement of a valve device onthe last car in the train to an emergency position occurring during thetime a brake release is being made after effecting a reduction ofpressure in the train brake pipe that is in excess of the reductionrequired to obtain a full service brake application on the entire train,prevents a sufficient rapid rate of reduction of the pressure in thatportion of the train brake pipe extending from end to end of thelocomotive and through the first several cars nearest the locomotive tocause operation of the charging cut-off pilot valve device on thelocomotive to effect the supply of fluid under pressure to the brakepipe cut-off valve and also operation of the brake control valve on thelocomotive and these cars to effect an emergency brake applicationthereon.

Accordingly, it is the general purpose of this invention to providemeans operable responsively to a chosen difference in the pressuresdeveloped on opposite sides of a restriction disposed in a conduitthrough which fluid under pressure flows from the main reservoir on thelocomotive to the train brake pipe via the brake pipe cut-off valve ofthe brake valve as the result of an emergency rate of reduction in thepressure of the fluid under pressure in the train brake pipe initiatedat a location in the train remote from the locomotive, as a result of aruptured or separated brake pipe or movement of a valve device on thelast car in the train to an emergency position, occurring whileeffecting a brake release subsequent to effecting a reduction ofpressure in the train brake pipe that is in excess of the reductionrequired to obtain a full service brake application on the entire train,to cause closure of this brake pipe cut- SUMMARY OF THE INVENTIONAccording to the present invention, a locomotive brake control apparatushas embodied therein a rate of flow responsive valve device comprising apair of diaphragm-operated spool-type valves, the diaphragm of one ofwhich is subject on its respective opposite sides to the pressuresdeveloped on the opposite sides of a restriction disposed in a supplyconduit connecting the main reservoir to a brake valve on thelocomotive. The diaphragm of the other spool-type valve is subject onits respective opposite sides to brake pipe pressure and pressure in avolume supplied with fluid under pressure from the brake pipe via twoparallel communications extending through the first spool-type valve,there being a check valve device disposed in one of these communicationsto prevent back flow in the direction of the brake pipe. Upondevelopment of the required difference in pressures on the oppositesides of the restriction in response to flow of fluid under pressurefrom the main reservoir to the brake pipe by operation of the relayvalve of the brake valve, as a result of an emergency rate of reductionof brake pipe pressure effected at a location in the train remote fromthe locomotive, the first spool-type valve is operated to close that oneof the two parallel communications that does not have the check valvedevice therein. The second spool-type valve is thereafter operated inresponse to the reduction of the pressure in the train brake pipe toeffect the supply of fluid under pressure from the main reservoir to thebrake pipe cut-off valve to cause the closing thereof therebyterminating further flow of fluid under pressure from the main reservoirto the train brake pipe. The continued release of fluid under pressurefrom the train brake pipe at the point of rupture or separation of thetrain brake pipe, or at the last car in the train, will now causeoperation of the charging cut-off pilot valve device on the locomotiveto effect the supply of fluid under pressure to the brake pipe cutoffvalve to maintain it closed independently of the rate of flow responsivevalve device, and also operation of the brake control valve device onthe locomotive and each car in the train to effect an emergency brakeapplication on the entire train.

In the accompanying drawings:

FIG. 1 is a diagrammatic view, in outline, showing a locomotive brakecontrol apparatus embodying theinvention, the engineer's brake valveincluded in this control apparatus being shown partly in outline andpartly in cross section.

FIG. 2 is a cross-sectional view, on an enlarged scale of the rate offlow responsive valve device shown in FIG. 1.

FIG. 3 is an enlarged view, in section, of the charging cut-off pilotvalve device shown in outline in FIG. 1.

FIG. 4 is an enlarged view, in section, of the flow indicator adaptershown in outline in FIG. 1.

As shown in FIG. 1 of the drawings, the conventional brake controlequipment heretofore provided on a locomotive is modified by theinclusion of a rate of flow responsive valve device 1 for effectingclosure of a brake pipe cut-off valve 2 of an engineers automatic brakevalve 3 on the locomotive in response to an emergency rate of reductionof pressure in a train brake pipe 4 initiated at a location in the trainremote from the locomotive.

This modified locomotive brake control equipment, which includes thepresent invention, further comprises a plurality of reservoirs includinga main reservoir 5, an equalizing reservoir 6 and a volume reservoir 7,a charging cut-off pilot valve device 8, a flow indicator adapter 9connected to the main reservoir by a supply pipe 10 and to the brakevalve 3 by a delivery pipe 11, and two identical vent valve devices 12connected respectively to the respective opposite ends of that portionof the train brake pipe 4 that extends from end to end of thelocomotive, it being noted that two vent valve devices per locomotiveunit are provided in order to insure releasing fluid under pressure fromthis portion of the train brake pipe at an emergency rate whenever anemergency brake application is effected in any manner at any location inthe train.

As shown in FIG. 2 of the drawings, the rate of flow responsive valvedevice 1 comprises a casing 13 having formed therein a pair of parallelspaced-apart bottomed bores 14 and 15 and a volume chamber 16. Slidablymounted in the bottomed bore 14 is a first spooltype valve 17, the upperend of which is provided with an annular flange 18 from which extends ascrewthreaded portion that passes through the center ofa diaphragm l9and a diaphragm follower 20 and receives a nut 21 that hasscrew-threaded engagement therewith to operatively connect thisdiaphragm 19 to the spooltype valve 17. The outer periphery of thediaphragm 19 is clamped between the upper end of the casing 13 and cover22 that is secured to this casing by any suitable means (not shown).

The diaphragm 19 cooperates with the casing 13 and the cover 22 to formwithin the flow responsive valve device 1 and on opposite sides of thediaphragm a first pair of chambers 23 and 24.

Disposed within the chamber 23 and interposed between the casing 13 andthe flange 18 is a spring 25 for biasing the valve 17 and the diaphragm19 in an upward direction to the position shown in which the nut 21abuts a stop 26 that is formed integral with the cover 22.

The spool-type valve 17 is provided with a pair of axially spaced-apartperipheral annular grooves in each of which is disposed an O-ring seal27 to prevent leakage of fluid under pressure between the periphery ofthe valve 17 and the wall ofthe bottomed bore 14, and with an elongatedperipheral annular groove 28 located between the two O-ring seals 27.This groove 28 is so located that, while the valve 17 occupies theposition shown, it connects that end of two passageways 29 and 30 in thecasing 13 that open at the wall surface of the bottomed bore 14, oneabove the other a distance equal to the length of the groove 28, withthat end of a third passageway 31 in the casing 13 that opens at thewall surface of this bottomed bore 14 diametrically opposite that end ofthe passageway 30 that opens at this wall surface.

The passageway 29 extends through the casing 13 and is connected to thebrake pipe 4 (FIG. 1) by a correspondingly numbered pipe. Likewise, thepassageway 30 extends through the casing 13 and is connected to theoutlet of a check valve device 32 by a correspondingly numbered pipe.The inlet of this check valve 32 is connected by a short pipe 33 to thepipe 29 intermediate the ends thereof. The purpose of this check valvedevice 32 is to provide for flow of fluid under pressure from the brakepipe 4 to the passageway 31 (FIG. 2) while the spool-type valve 17occupies a lower or second position in which the upper O-ring 27 carriedthereby forms a seal with the wall surface of the bottomed bore 14 at alocation below that end of the passageway 29 that opens at this wallsurface.

Slidably mounted in the bottomed bore 15 in the casing 13 is a secondspool-type valve 34, the upper end of which has formed integraltherewith an annular flange 35 from which extends a screw-threadedportion that passes through the center of a second diaphragm 36 and anannular diaphragm follower 37. A nut 38 has screw-threaded engagementwith this screw-threaded portion extending upward from the flange 35 andserves to clamp the annular inner edge of the diaphragm 36 rigidlybetween the flange 35 and the diaphragm follower 37 thereby operativelyconnecting the diaphragm 36 to the valve 34. The outer periphery of thediaphragm 36 is rigidly clamped between the upper end of the casing 13and the cover 22.

The diaphragm 36, like the diaphragm 19, cooperates with the casing 13and the cover 22 to form within the valve device 1 and on opposite sidesof the diaphragm a second pair of chambers 39 and 40. The other end ofthe above-mentioned passageway 31, and also the above-mentioned volumechamber 16, open into the chamber 39. Opening into the chamber 40 is oneend of a passageway 41 that extends through the cover 22 and casing 13and at its opposite end opens into the hereinbefore-mentioned passageway29 intermediate the ends thereof.

Disposed within the chamber 40 is a spring 42 that is interposed betweenthe diaphragm follower 37 and the cover 22. This spring 42 is effectiveto normally bias the flange 35 against a stop 43 integral with thecasing 13 to thereby position the spool-type valve 34 in the positionshown in FIG. 2 of the drawings. This valve 34 is provided with anelongated peripheral annular groove 44 and, adjacent each end of thisgroove 44, with a peripheral annular groove in which is disposed anO-ring seal 45 that forms a seal with the wall surface of the bottomedbore 15 to prevent leakage of fluid under pressure into the elongatedgroove 44 from the chamber 39 and from the bottomed bore 15. While thevalve 34 occupies the position shown, the elongated groove 44 thereonestablishes a communication between that end of each of a pair ofpassageways 46 and 47 in the casing 13 that open at the wall surface ofthe bottomed bore 15 one above-the other a distance equal to the lengthof the groove 44. The lower O-ring seal 45 carried by this valve 34closes communication between the passageway 47 and that end of apassageway 48 formed in the casing 13 and opening at one end at the wallsurface of the bottomed bore 15. This passageway 48 is connected by acorrespondingly numbered pipe to the hereinbefore-mentioned supply pipe10 (FIG) 1) intermediate the ends thereof. The passageway 46 (FIG. 2)extends through the casing 13 to the exterior thereof thus forming anexhaust to atmosphere, and the passageway 47 is connected by acorrespondingly numbered pipe to one input of a double check valvedevice 49 (FIG. 1) the other inlet of which is connected to thehereinbefore-mentioned charging cut-off valve device 8 which will not bedescribed in detail.

The charging cut-off pilot valve device 8 is shown diagrammatically inFIG. 3 of the drawings and comprises a pipe bracket 50 that is providedon its lower side with a bolting face 51 to which is secured by anysuitable means (not shown) a casing 52.

Extending upward form the bolting face 51 through the pipe bracket 50are seven ports and corresponding passageways which open at the upperside of the pipe bracket 50 these being denoted by the numerals 53, 54,55, 56, 57, 58 and 59.

The above-mentioned other outlet of the double check valve device 49(FIG. 1) is connected by a pipe 60 to the port 53 (FIG. 3) at the upperside of the pipe bracket 50 and the corresponding passageway 53 extendsthrough the pipe bracket 50 and casing 52 and opens at its other end atthe wall surface of bore 61 extending through the casing 52.

Connected to the port 54 is one end of a pipe 62 the opposite end ofwhich is connected to the usual sanding equipment provided onlocomotives. This sanding equipment has been omitted from the drawingssince it forms no part of the present invention.

Opening at the wall surface of the bore 61 at a location on theleft-hand side of the location at which the passageway 53 opens at thiswall surface is one end of the above-mentioned passageway 57 thatextends through the casing 52 and pipe bracket 50 and is connected by acorrespondingly numbered pipe to the hereinbefore-mentioned pipe 48intermediate the ends thereof, it being remembered that this pipe 48 isconnected to the supply pipe that is connected to the main reservoir 5(FIG. 1).

The port 58 (FIG. 3) at the upper side of the pipe bracket 50 isconnected by a correspondingly numbered pipe to the brake pipe 4, asshown in Flg. l. The corresponding passageway 58 (FIG. 3) extendsthrough the casing 52 and opens at the left-hand end ofa counterbore 63therein that is coaxial with a bore 64 in this casing 52. Slidablymounted in the bore 64 is a spooltype valve 65 that has formed integraltherewith at its right-hand end an actuating piston 66 which is slidablymounted in the counterbore 63.

The actuating piston 66 is provided with a peripheral annular groove inwhich is disposed an O-ring seal 67 that forms a seal with the wallsurface of the counterbore 63 to prevent leakage of fluid under pressurebetween the periphery of the piston 66 and the wall of the counterbore63 from a chamber 68 on the right-hand side of the piston to theleft-hand end of the counterbore 63. Opening into the chamber 68 is oneend of the hereinbefore-mentioned passageway 59 that extends through thecasing 52 and pipe bracket 50 and is connected by a correspondinglynumbered pipe to the volume reservoir 7 (FIG. 1).

In order to provide for charging the volume reservoir 7 (FIG. I) fromthe brake pipe 4, the piston 66 (FIG. 3) and spool-type valve 65 haveformed therein a bottomed bore 69 the left-hand end of which, as viewedin FIG. 3, is open to the interior of the counterbore 63 via a shortpassageway 70. The right-hand end of the bottomed bore 69 is providedwith internal screw threads for receiving a screw-threaded choke plug71. Consequently, fluid under pressure flows from the brake pipe 4 tovolume reservoir 7 via pipe and corresponding passageway 58, thatportion of the counterbore 63 on the left-hand side of the piston 66,short passageway 70, bottomed bore 69, a strainer device 72, disposed inthe bottomed bore 69, choke plug 71, chamber 68, and passageway andcorresponding pipe 59 until the volume reservoir 7 is charged to thenormal chosen pressure to which the brake pipe 4 is charged.

As shown in FIG. 3, the spool-type valve 65 has formed thereon anelongated peripheral annular groove 73 and adjacent each end of thisgroove, a pair of spaced-apart peripheral annular grooves in each ofwhich is disposed an O-ring seal 74 that forms a seal with the wallsurface of the bore 64.

When the spool-type valve 65 is moved by the piston 66, in a mannerhereinafter explained, from the position shown in FIG. 3 against theyielding resistance of a spring 75 to a second position, the groove 73establishes a communication between a passageway 76, one end of whichopens at the wall surface of the bore 64 and the opposite end of whichopens into the passageway 57 intermediate the ends thereof, and apassageway 77 one end of which opens at the wall surface of the bore 64on the left-hand side of the location at which the one end of thepassageway 76 opens at the wall surface of this bore.

The passageway 77 extends through the casing 52 -and at its other endopens into a chamber 78 formed between'a cut-off piston 79 that isslidably mounted in a counterbore 80 coaxial with the bore 61 in thecasing 52 and a cover member 81 that closes the left-hand ends of thebore 64 and the counterbore 80 and is secured to the casing 52 by anysuitable means (not shown). I

Opening into the passageway 77 intermediate the ends thereof is thehereinbefore-mentioned passageway 54 to the corresponding port of whichis connected one end of the pipe 62 leading to the locomotive sandingequipment, as aforestated.

Formed integral with the cut-off piston 79 is a spooltype valve 82 thatis slidably mounted in the bore 61 and has formed thereon an elongatedperipheral annular groove 83. This spool-type valve 82 is furtherprovided with a bottomed bore 84ithe right-hand end of which hasinternal screw threads for receiving a screwthreaded plug 85 to closethe right-hand end of this bottomed bore. Adjacent its left-hand end thebottomed bore 84 is open to the interior of the counterbore 80 via ashort passageway 86. Likewise, adjacent its righthand end the bore 84 isopen to the peripheral surface of the valve 82 via a short passageway 87which, while the valve 82 occupies the position shown in FIG. 3,registers with the hereinbefore-mentioned one end of the passageway 57that opens at the wall surface of the bore 61. Since the passageway 57is connected by the correspondingly numbered pipe, the pipe 48 (FIG. 1)and supply pipe 10 to the main reservoir 5, fluid under pressure flowsfrom this reservoir to the right-hand face of the piston 79 (FIG. 3) viapipes 10 and 48, pipe and passageway 57, short passageway 87, bottomedbore 84, short passageway 86 and counterbore 80, and is effective tonormally maintain the piston 79 and valve 82 in the position shown inFIG. 3.

The charging cut-off pilot valve device 8 further comprises a pair ofspaced-apart identical check valve devices 88 and 89. Therefore, adescription of one will suffice for both, it being understood thatcorresponding parts of the check valve device 89 have the same referencenumerals as those of the check valve device 88.

Each of the check valve devices 88 and 89 comprises a flat disc valve 90which is slidably disposed in a counterbore 91 formed in a cap nut 92that has screwthreaded engagement with corresponding internal screwthreads provided'in the casing 52, and is biased toward a correspondingvalve seat by a spring 93 interposed between the flat disc valve 90 andthe cap nut 92.

To facilitate assembly and disassembly of the cap nut 92, spring 93 andflat disc valve 90 as a unit, the spring 93 and flat disc valve 90 areretained in the counterbore 91 by a snap ring 94 that is inserted in agroove formed in the wall of this counterbore.

As shown in FIG. 3, the spring 93 of the check valve device 88 iseffective to normally bias the corresponding flat disc valve 90 againstan annular valve seat 95 that is formed at one end of a passageway 96that extends through the casing 52 and opens at its opposite end at thewall surface of the bore 61 on the left-hand side of the location atwhich the hereinbeforementioned one end of the passageway 57 opens atthis wall surface a distance equal to the length of the groove 83. Whilethe spool-type valve 82 occupies the position shown in FIG. 3, thegroove 83 thereon establishes a communication between the passageway 96and a passageway 97 that is open to atmosphere.

Opening into the passageway 96 intermediate the ends thereof is thehereinbefore-mentioned passageway 55 to the corresponding port of whichis connected one end of a pipe 98 that has its opposite end connected tothe right-hand inlet ofa second double check valve device 99 (FIG. 1).

The cap nut 92 (FIG. 3) of the check valve device 88 cooperates with thecasing 52 to form therein a chamber 100 into which opens one end of ashort passageway 101 that at its opposite end opens into thehereinbefore-mentioned passageway 53 intermediate the ends thereof.

As is also shown in FIG. 3, the spring 93 of the check valve device 89is effective to normally bias the corresponding flat disc valve 90 ofthis check valve device against an annular valve seat 102 that is formedat one end of the hereinbefore-mentioned passageway 56 to thecorresponding port of which is connected one end of a pipe 103 theopposite end of which is connected to the left-hand inlet of thehereinbefore-mentioned double check valve device 99 (FIG. .1).

The cap nut 92 (FIG. 3) of the check device 89 cooperates with thecasing 52 to form therein a chamber 104 into which opens one end of apassageway 105 that extends through the casing 52 and opens into thebore 61 therein adjacent the right-hand end thereof which is closed by acover member 106 that also closes the right-hand end of the counterbore63 and is secured to the casing 52 by any suitable means (not shown).

The engineer's automatic brake valve 3 (FIG. 1) may be of theself-lapping type such as that disclosed in US. Pat. No. 2,958,561,issued November 1, 1960 to Harry C. May, and assigned to the assignee ofthe present application.

The brake valve 3 (FIG. 1) comprises a relay valve 107, a self-lappingregulating or control valve 108, and the hereinbefore-mentioned brakepipe cut-off valve 2.

Relay valve 107 comprises a diaphragm 109 (FIG.

1), which is subject opposingly to fluid pressures in a chamber 110 anda chamber 111 and is adapted through the medium of a coaxially arrangedoperating stem 112 to effect unseating of a disc-shaped exhaust valve113 carried by an annular valve member 114, or effect unseating of adisc-shaped supply valve 115 carried by a coaxially arranged annularvalve member 1 16, according to whether pressure in chamber 110 is lessthan or exceeds the pressure in chamber 1 11. Stem 112 is coaxiallyconnected to the chamber 111 side of diaphragm 109 and projectscentrally through valve member 114 and through a chamber 117 and isadapted to abut one end of supply valve member 116. Helical springs 118,119 urge the valve members 114, 116 toward each other for normallyconcurrently seating the valves 113, 115. Exhaust valve 113 controlscommunication between chamber 1 17 and a chamber 120 which is open toatmosphere via a passageway 121 and an exhaust choke 122; whereas supplyvalve 115 controls communication of chamber 117 with a supply chamber123 that is always open to main reservoir 5 via a passageway 124 to oneend of which is connected one end of the hereinbefore-mentioned deliverypipe 11, the pipe 11, flow indicator adapter 9 hereinafter described indetail and the supply pipe 10.

The brake pipe cut-off valve 2 comprises an annular cut-off valve 125that is disposed in a chamber 126 which is constantly in communicationwith the brake pipe 4 via a passageway and correspondingly numbered pipe127 that is connected to the hereinbeforementioned pipe 29 intermediatethe ends thereof which pipe 29 is connected to the brake pipe 4, asaforestated. This cut-off valve 125 controls communication between achamber 128 that is connected respectively to the chamber 117 by apassageway 129 and to the chamber 111 by a branch passageway 129a andthe chamber 126, and is carried by an annular member 130 normally biasedagainst an annular valve seat 131 by a spring 132 interposed between theannular member 130 and one side of a piston member 133. A second spring134 is interposed between the opposite side of the piston member 133 anda cover member l35'secured to a main casing 136 of the sectionalizedcasing of the brake valve 3 by any suitable means (not shown). Anannular chamber 137 at the right-hand side of the piston member 133 isconstantly open to atmosphere via an exhaust passageway and port 138,and a chamber 139 at the left-hand side of this piston member133 isnormally vented to atmosphere via a passageway and correspondinglynumbered pipe 140 that is connected to the outlet connection of thehereinbefore-mentioned double check valve device 49 and one or both oftwo pathways now to be described, depending on the position of the valveelement (not shown) of this valve device 49.;

If the valve element of the double check valve device 49 is in theposition in which communication between the pipes 140 and 47 is closed,the chamber 139 at the left-hand side of the piston member 133 is opento atmosphere via the passageway 140, a passageway 141 one end of whichopens into the passageway 140 intermediate the ends of this passageway140 and the opposite end of which opens at the wall surface of a bore142 provided in a second casing section 143 of the sectionalized casingof the brake valve3 that incorporates therein a manually operatedcut-off valve 144, ,a peripheral annular groove 145 formed on aspool-type valve 146 slidably mounted in the bore 142, a choke 147 and apassageway 148 in the spool-type valve 146, a chamber 149 in the casingsection 143 and a port 150 provided in this casing section.

If the valve element of the double check valve device 49 is in theposition in which a communication between the pipes 140 and 47 is open,the camber 139 is open to atmosphere via the pathway described above andalso via passageway and pipe 140, double check valve device 49, pipe andpassageway 47, groove 44 (FIG. 2) on valve 34 and exhaust passageway 46in casing 13 of rate of flow responsive valve device 1.

The hereinbefore-mentioned flow indicator adapter 9 (FIG. 4) comprises acasing 151 having therein two chamber 152 and 153 into which openrespectively one end of the supply pipe and the delivery pipe 11 andalso respectively one end of a pair of pipes 154 and 155. The other endof the pipe 154 opens into the chamber 24 (FIG. 2) at the upper side ofthe diaphragm 19, and the other end of the pipe 155 opens into thechamber 23 at the lower side of this diaphragm 19. The chambers 152 and153 (FIG. 4) are connected by two parallel bores 156 and 157, the bore157 being of small diameter so as to constitute a choke. An annularvalve seat 158 is formed at the upper end of the bore 156 and a checkvalve 159 is normally biased against this valve seat 158 by a spring 160that is interposed between this check valve and a spring seat 161 thatabuts a snap ring 162 carried by the casing 151.

Each of the two vent valve devices 12 shown in outline in FIG. 1 of thedrawings may be of the type such as that disclosed in U.S. Pat. No.3,l65,l 15, issued Jan. 12, I965, to Erik G. Erson, and assigned to theassignee of the present application, and, in view of this, it isbelieved unnecessary to show and describe this device in detail.Briefly, however, as described in the abovementioned patent, each ventvalve device 12 is operative in response to only a reduction of thepressure in the train brake pipe 4 at an emergency rate to locally ventfluid under pressure from the brake pipe 4 at a rapid rate.

Connected to the hereinbefore-mentioned pipe 103 intermediate the endsthereof is one end of a pipe 163 the opposite end of which is connectedto a correspondingly numbered passageway that leads to an emergencyvalve 164 of the brake valve 3, it being understood that this emergencyvalve forms no part of the present invention. Briefly, however, thisemergency valve 164 is operative to supply fluid under pressure to thepipes 163 and 103 upon movement ofa handle 165 of the brake valve 3 toits emergency position. Fluid under pressure thus supplied to the pipe103 flows via the double check valve device 99 and a pipe 166 to a powercut-off switch 167 to cause cut off of the supply of electrical currentto the driving motors of the locomotive, it being noted that a branchpipe 166a connects the pipe 166 to a dynamic brake cut-out switch 168 sothat the dynamic brake is simultaneously cut out. Furthermore, the fluidunder pressure supplied to the pipe 103 flows to the right-hand end ofthe bore 61 (FIG. 3) via passageway 56, past check valve 90 of doublecheck valve device 89, chamber 104 and passageway 105 to move the valve82 and piston 79 to the position shown in FIG. 3 if they have beenpreviously moved to this position.

OPERATION To initially charge the brake control equipment shown in FIG.1 of the drawings, the diesel engines are started for operating fluidcompressors (not shown) to effect charging of the main reservoir 5.

It may be assumed that the handle 165 of engineer's automatic brakevalve 3 shown in FIG. 1 of the drawings is in its release position andthe spool-type valve 146 of the manually operated cut-off valve 144occupies the position shown. Therefore, while the brake valve handle 165is in its release position, the selflapping regulating valve 108 of thisbrake valve 3 is effective, as explained in the above-mentioned US. Pat.No. 2,958,561, to supply fluid under pressure from the main reservoir 5,which is connected to this regulating valve device via supply pipe 10,flow indicator adapter 9, pipe 11, passageway 124 and a branch 1240 ofthis passageway, to the equalizing reservoir 6 and chamber in the relayvalve 107. Consequently, the relay valve 107 will operate to effect thesupply of fluid under pressure from the supply chamber 123, that isconnected to the main reservoir 5 via the passageway 124, pipe 11, flowindicator adapter 9 and pipe 10, to the chamber 117 from whence it willflow to the chamber 128 and unseat the cut-ofi valve from its seat Withcut-off valve 125 unseated, fluid under pressure supplied to the chamber128 from the main reservoir 5 will flow past this valve 125 and thenceto the train brake pipe 4 via passageway and pipe 127 and pipe 29. Thus,fluid under pressure is supplied from the main reservoir 5 on thelocomotive to the train brake pipe until this pipe is fully charged tothe pressure normally carried therein as determined by the setting ofthe regulating valve 108. t

The brake control valves (not shown) on the locomotive and cars in thetrain will operate in response to the charging of the train brake pipeto effect a release of the brakes on the entire train.

A service brake application and a subsequent brake release on thelocomotive and cars in the train can be effected in the usual manner andneed not be described in detail herein since the present inventionrelates only to an emergency brake applicationinitiated at a location inthe train brake pipe remote from the locomotive.

Let it now be supposed that, while effecting a brake release on thelocomotive and cars in the train, subsequent to effecting a reduction ofpressure in the train brake pipe that is in excess of the reductionrequired to obtain a full service brake application on the entire train,the hose connection between two adjacent cars in the train remote fromthe locomotive becomes ruptured or separated, or a valve device on thelast car in the train is manually moved to aposition for releasing fluidunder pressure from the train brake pipe to atmosphere at an emergencyrate.

As fluid under pressure is thus released from the train brake pipe, thepressure therein will be reduced progressively from the point of releasetoward the locomo tive at the head end of the train, it being understoodthat farther from the point of release, the higher will be the pressurein the train brake pipe.

It being remembered that the handle of the brake valve 3 on thelocomotive now occupies its release position, the relay valve 107 ofthis brake valve 3 will operate in response to this reduction ofpressure in the train brake pipe effected at a location from thelocomotive to cause the supply of fluid under pressure from the mainreservoir 5 to that portion of the train brake pipe 4 extending from endto end of the locomotive simultaneously as fluid under pressure isreleased from the train brake pipe to atmosphere at this location remotefrom the locomotive. Consequently, the reduction of pressure in thatportion of the train brake pipe 4 extending from end to end of thelocomotive is not sufficiently rapid to cause operation of the two ventvalve devices 12 connected thereto, as shown in FIG. 1, since, asexplained in the hereinbefore-mentioned U.S. Pat. No. 3,165,l 15, thesevent valve devices operate to release fluid under pressure from thetrain brake pipe to atmosphere only in response to an emergency rate ofreduction of pressure in the brake pipe.

Especially in the case of a long train, without operation of these twovent valve devices 12 to release additional fluid under pressure fromthat portion of the train brake pipe 4 extending from end to end of thecomotive to atmosphere, the rate of reduction of pressure effected inthis portion of the train brake pipe is not in excess of the rate atwhich fluid under pressure can flow from the volume reservoir 7 to thetrain brake pipe 4 via pipe and passageway 59, chamber 69 (FIG. 3), thechoke plug 71 carried by the actuatihg piston 66 of the charging cut-offpilot valve device 8, strainer device 72, passageway 70, counterbore 63and passageway and pipe 58. Therefore, a differential of pressuresufficient to overcome the yielding resistance of the spring 75 is notestablished on the opposite sides of the actuating piston 66 and thecharging cut-off pilot valve device 8 is not operated in response toeither the rupture or separation of the hose connection between the twocars in the train remote from the locomotive, or the manual movement ofthe valve device of the last car in the train to the position forreleasing fluid under pressure from the train brake pipe to atmosphereat, an emergency rate.

Since the charging cut-off pilot valve device 8 is not operated inresponse to the emergency rate of reduction of pressure in the trainbrake pipe effected at the location remote from the locomotive, no fluidunder pressure is supplied by this valve device 8 to the chamber 139(FIG. 1) in the brake pipe cut-off valve 2 of the brake valve 3 on thelocomotive to cause seating of the cut-off valve 125 on the seat 131 toprevent the supply of fluid under pressure from the main reservoir 5 tothe train brake pipe 4 by operation of the relay valve 107 of brakevalve 3. Consequently, fluid under pressure will continue to flow fromthe main reservoir 5 to the train brake pipe 4 via supply pipe 10, flowindicator adapter 9, pipe 11, passageway 124, relay valve 107,passageway 129, brake pipe cut-off valve 2, passageway and pipe 127 andpipe 29.

It is apparent that as fluid under pressure flows from 12' sides of -thediaphragm l9 reaching a value z of, for example, 8 pounds per squareinch, this diaphragm 19 is deflected in a downward direction against theyielding the main reservoir 5 to the train brake pipe 4 in the mannerjust described, a difference of pressure in the chambers 152 and 153(FIG. 4) in the flow indicator adaptor 9 is produced which increases inmagnitude accordingly as the rate of flow of fluid under pressure fromthe main reservoir 5 to the brake pipe 4 increases.

Since the chamber 152 (FIG. 4) is connected to the chamber 24 (FIG. 2)in the rate of flow responsive valve device 1 via the pipe 154, and thechamber 153 is connected to the chamber 23 in this valve device 1 viathe pipe 155, a corresponding difference of pres sure is produced in thechambers 24 and 23 which establishes a differential on the respectiveopposite sides of the diaphragm 19.

The strength of the spring 25 may be such that, upon the difference inthe pressures acting on the opposite resistance of the spring 25 to movethe valve 17 in the same direction to a position in which the upperO-ring seal 27 carried by this valve 17 forms a seal with the wallsurface of the bottomed bore 14 at a location below that at which theend of the passageway 29 opens at this wall surface, thus closingcommunication between the passageway 29 and the passageway 31 which isconnected to the chamber 39 below thediaphragm 36, it being rememberedthat the volume chamber 16 opens into the chamber 39. Consequently, thefluid under pressure in the chamber 39 and in the volume chamber 16 istrapped therein by the check valve 32 (FIG. 1) which prevents back flowto the brake pipe 4.

Since the chamber 40 (FIG. 2) above the diaphragm 46 is connected to thebrake pipe 4 via the passageway 41 and passageway and pipe 29, thepressure in the chamber 40 will be reduced simultaneously as thepressure in the brake pipe 4 is reduced.

The strength of the spring 42 may be such that, upon the pressure in thechamber 40 becoming, for example, 5 pounds per square inch less than thetrapped pressure in the chamber 39, this trapped pressure will deflectthe diaphragm 36 upward against the yielding resistance of the spring 42and move the valve 34 upward therewith to a position in which the lowerO-ring seal 45 carried by the valve 34 forms a seal with the wallsurface of the bottomed bore 15 at a location that is above the locationat which the end of the passageway 47 opens at this wall surface andbelow that at which the end of the exhaust passageway 46 opens at thiswall surface.

When the valve 34 is moved upward to the position just described, fluidunder pressure will flow from the main reservoir 5 to the chamber 139 inthe. brake pipe cut-off valve device 2 of the engineer's brake valve 3via supply pipe 10, pipe and passageway 48, bottomed bore 15, passagewayand pipe 47, double check valve device 49, and pipe and passageway 140.This supply of fluid under pressure to the chamber 139 effects movementof the piston member 133 and annular member 130 in the direction of theright hand until cutoff valve is seated on valve seat 13 1 therebypreventing further supply of fluid under pressure from the mainreservoir 5 on the locomotive to the train brake pipe by operation ofthe relay valve 107 of the brake valve 3.

It is apparent that, subsequent to the seating of the;

cut-off valve 125 on its seat 131 in the manner just explained to renderthe relay valve 107 ineffective to operate to supply fluid underpressureto the train brake pipe, thepressure therein willbe rapidly reducedasthe result of the release of fluid under pressure therefrom at anemergency rate at the point of rupture or separation of the hoseconnection between two adjacent cars in the train remote from thelocomotive, or via the valve device located on the last car in thetrain. Consequently, an emergency rate of reduction of pressure in thatportion of the train brake pipe extending from end to end of thelocomotive is quickly developedas fluid under pressure flows through thetrain brake pipe from the locomotive toward the remote point of releaseof fluid under pressure therefrom at an emergency rate.

Accordingly, upon the rate of reduction of pressure in that portion ofthe train brakepipe4 extending from end to end of the locomotivereaching an emergency rate, subsequent to seating of the cut-off valve125 on its seat 131 to prevent further supply of fluid under pressure tothe train brake pipe by the relay valve 107,

.the two vent valve devices 12 will operate, in the manner explained inhereinbefore-mentioned U.S. Pat. No. 3, 1 65,1 15, to vent additionalfluid under pressure from this portion of the train brake pipe toatmosphere. Therefore, it is apparent that fluid under pressure is nowflowing from that portion of the train brake pipe extending from end toend of the locomotive at a faster rate than fluid under pressure canflow from the volume reservoir 7 to the train brake pipe via pipe andpassageway 59, chamber 68 (FIG. 3), choke plug 71, strainer 72, shortpassageway 70, that portion of counterbore 63 on the left-hand side ofpiston 66 and passageway and pipe 58 since the size of the choke plug 71is such as to prevent the flow of fluid under pressure therethrough atan emergency rate. Consequently, a pressure differential is quicklyestablished on the opposite sides of the piston 66 which moves thispiston and the valve 65 in the direction of the left hand against theyielding resistance of the spring 75 to a position in which the groove73 on the valve 63 establishes a communication between the passageways76 and 77.

Upon the establishment of a communication between the passageways 76 and77 in the manner just described, fluid under pressure will flow from themain reservoir (FIG. 1) to the chamber 78 (FIG. 3) on the left-hand sideof the piston 79 via supply pipe 10, pipe 48, pipe and passageway 57,passageway 76 (FIG. 3), groove 73 and passageway 77. This supply offluid under pressure from the main reservoir 5 to the chamber 78 willeffect movement of the piston 79 and valve 82 in the direction of theright hand since main reservoir pressure acting on the right-hand sideof piston 79 is acting on an area equal to the difference in the area ofthe piston 79 and the area of the spool-type valve 82.

The piston 79 and valve 82 will be moved in the direction of the righthand in the manner just explained until the groove 83 on this valve 82establishes a communication between the passageways 57 and 96. Since thepassageway and pipe 57 are connected to the main reservoir 5 via thepipes 48 and 10, fluid at main reservoir pressure will flow from thepassageway and pipe 57 to the passageway 96, it being noted from FIG. 3that one end of the passageway is connected to the passageway 96intermediate the ends thereof and the opposite end of this passageway 55is connected to the pipe 98.

It can be seen from FIG. 1 of the drawings that the fluid under pressurethus supplied to the pipe 98 flows to the right-hand end of the doublecheck valve device 99 to move a check valve element therein (not shown)to a position to establish a communication between the pipes 98 and 166.Therefore, upon the establishment of a communication between the pipes98 and 166, fluid under pressure supplied to the pipe 98 flows via thedouble check valve device 99 and pipe 166 to the power cut-off switch167 to cause cut off of the supply of electrical current to the drivingmotors of the locomotive in the usual manner.

Part of the fluid under pressure supplied to the pipe 166 in the mannerexplained above flows through the branch pipe 166a to the dynamic brakecut-out switch 168 to cause cut out of the dynamic brake on thelocomotive.

Referring to FIG. 3, it can be seen that fluid under pressure suppliedto the passageway 96, as explained above, flows to the right-hand sideof the flat disc valve of the check valve device 88 and unseats thisvalve 90 from its seat against the yielding resistance of the spring 93.Upon thus unseating the valve 90, fluid at main reservoir pressurepresent in the passageway 96 flows past the unseated valve 90 to thechamber 100 and thence through the short passageway 101 to thepassageway 53 which is connected to the right-hand inlet of the doublecheck valve device 49 (FIG. 1) by the pipe 60.

It will be understood that the supply of fluid under pressure from themain reservoir 5 to the chamber 139 in the brake pipe cut-off valve 2upon movement of the spool-type valve 34 (FIG. 2) to its upper positionin the manner hereinbefore-described, moved the double check valveelement (not shown) of the double check valve device 49 to itsright-hand position in which a communication is established betweenpipes 47 and 140 and communication is closed between pipes 60 and 140.Consequently, the fluid under pressure supplied to the pipe 60 isineffective to move the valve element of the double check valve device49 to its left-hand position so long as the spool-type valve 34 (FIG. 2)occupies its upper position in which fluid under pressure from the mainreservoir 5 is supplied to the pipe 47 in the manner hereinbeforeexplained.

As soon as the cut-off valve of the brake pipe cut-off valve 2 is seatedon its seat 131 in the manner hereinbefore explained, flow of fluidunder pressure through the flow indicator adapter 9 ceases.Consequently, the pressures in the chambers 152 and 153 (FIG. 4) in thisadapter 9, and likewise in the chambers 24 and 23 (FIG. 2) on theopposite sides of the diaphragm 19, quickly equalize, it beingremembered that the chambers 152 and 153 are connected by the passageway157 which constitutes a choke, as hereinbefore stated. I

Upon equalization of pressure in the chambers 23 and 24 in the mannerjust explained, the spring 25 is rendered effectiveto deflect thediaphragm 19 upward and move the valve 17 upward until it is returned tothe position shown vin FIG. 2 in' which the groove 28 thereonreestablishes a communication between the passageways 31 and 29. Uponhis reestablishment of the communication between passageways 31 and 29,the fluid under pressure presentinthe volume chamber 16and the chamber39 below the diaphragm 36 flows to the chamber 40 above 'this diaphragmvia the passageway 31, groove 28, passageway 26 and passageway 41 untilthe pressures in the chambers 39 and 40 equalize, it being noted thatthe passageway 29 is connected by the correspondingly numbered pipe tothe train brake pipe 4 which, it will be remembered, is open toatmosphere either at the point of rupture or separation of the hoseconnection between two cars in the train, or at the last car in thetrain. Consequently, subsequent to equalization of pressure in thechambers 39 and 40, all fluid under pressure in these chambers is ventedto atmosphere and the pressure therein becomes atmospheric.

Upon equalization of pressure in the chambers 39 and 40 on the oppositesides of the diaphragm 36, the spring 42 is rendered effective to returnthe diaphragm 36 and the valve 34 to the position shown in FIG. 2 of thedrawings.

Upon the return of the valve 34 to the position shown in FIG. 2, thegroove 44 on this valve 34 establishes a communication between the pipeand passageway 47 and the exhaust passageway 46. Consequently, fluidunder pressure will be vented from the left-hand side of the valveelement of the double check valve 49 (FIG. 1) to atmosphere.

As fluid under pressure is thus vented from the lefthand side of thevalve element in the double check valve device 49, the fluid underpressure present in the pipe 60 will move this valve element to itsleft-hand position and then flow to the chamber 139 in the brake pipecut-off valve 2 via this double check valve device 49 and the pipe andpassageway 140. Consequently, the cut-off valve 125 is maintained seatedon its seat 131 subsequent to the return of the spool-type valves 17 and34 of the rate of flow responsive valve device 1 to the position inwhich they are shown in FIG. 2 to prevent the relay valve 107 fromsupplying fluid under pressure to the train brake pipe.

At the time piston 66 and valve 65 (FIG. 3) of the charging cut-offpilot valve device 8 were moved to their left-hand position in themanner hereinbefore described, the right-hand O-ring seal 74 carried ina pcripheral annular groove provided therefor in the valve 65 is movedto a position in which it makes a seal with the wall surface of the bore64 on the left-hand side of the location at which a choked exhaust'port169 opens at the wall surface of this bore 64. Therefore, all of thefluid present in the volume reservoir 7 will flow at a slow rate toatmosphere via pipe and passageway 59, chamber 68, choke plug 71,strainer device 72, short passageway 70, bore 64 and choked exhaust port169. Therefore, subsequent to flow of all the fluid under pressure inthe volume reservoir 7 and chamber 68 to atmosphere so that the pressuretherein is reduced to atmospheric pressure, the spring 75 will move thespool-type valve 65 and piston 66 in the direction ofthe right hand tothe position shown in FIG. 3, whereupon fluid under pressure in thechamber 78 is vented to atmosphere via passageway 77, a passageway 170in the valve 65 which passageway at one end registers with that end ofthe passageway 77 that opens at the wall surface of the bore 64 and atthe opposite end with the choked exhaust port 169, and this exhaustport.

To effect restoration of the piston 79 and valve 82 in the chargingcut-off pilot valve device 8 to their original position subsequent torepair of the rupture of the hose connection between two adjacent carsin the train, or recoupling of the separated hose couplings, or manualmovement of the valve device on the last car in the train back to itsoriginal position to cut off the flow of fluid under pressuretherethrough from the train-brake pipe to atmosphere, the engineer willmove the handle 165 (FIG. 1) of the brake valve 3 from its releaseposition to its emergency position.

As explained in hereinbefore-mentioned US. Pat. No. 2,958,561, when thehandle 165 of the brake valve 3 is moved to its emergency position, acam 171 that is mounted on a cam shaft 172, to the upper end of whichthe handle 165 is secured, shifts a spool-type valve 173 of theemergency valve 164 in the direction of the left hand from the positionshown in FIG. 1 to a position in which an elongated peripheral annulargroove 174 formed on this valve 173 establishes a communication betweenone end of a passageway 175 and the passageway and pipe 163. The otherend of the passageway 175 opens into the passageway 124 intermediate theends thereof, it being remembered that this passageway 124 is connectedto the main reservoir 5 via pipe 11, flow indicator adapter 9 and pipe10. Consequently, fluid under pressure will now flow from the mainreservoir 5 to the passageway and pipe 163 and thence to the right-handend of the bore 61 (FIG. 3) via pipe 103, passageway 56, pastspring-loaded valve of the check valve device 89, chamber 104 andpassageway 105. Fluid under pressure thus supplied to the right-hand endof the bore 61 acts on the right-hand end of the spool-type valve 82 andmoves this valve and the piston 79 in the direction of the left hand tothe position shown in FIG. 3.

The fluid under pressure thus supplied to the righthand end of the bore61 will now flow therefrom to the chamber 139 (FIG. 1) via passageway53, pipe 60, double check valve device 49 and pipe and passageway 140.However, upon subsequent movement of the brake valve handle 165 back toits release position, fluid under pressure present in the chamber 139will be vented at a slow rate to atmosphere via passageways 140 and 141,groove on spool-type valve 146, choke 147 and passageway 148 in thisvalve 146, chamber 149 and port 150.

After all fluid under pressure is thus vented from the chamber 139, thefluid under pressure supplied to the chamber 128 by the relay valve 107will unseat the cutoff valve 125 from its seat 131 to establish acommunication between the passageway 129 and passageway and pipe 127, itbeing noted that pipe 29rconnects pipe 127 to train brake pipe 4.

The relay valve 107 will now operate to charge the train brake pipe toeffect a brake release on the entire train in the usual manner.

Having now described the invention, what we claim as new and desire tosecure by Letters Patent, is:

1. A locomotive brake control apparatus for controlling the brakes onthe locomotive and the cars in a train, the combination of:

a. normally charged brake pipe, variations of the fluid pressure inwhich are effective to control brake applications and brake releases onthe locomotive and cars,

b. a normally charged main reservoir,

c. a normally charged equalizing reservoir,

d. a brake'valve having:

' i. a relayvalve which is subject to the opposing pressures in saidequalizing reservoir and said brake pipe and is operative by thedifferential of the pressures in said equalizing reservoir and in saidbrake pipe to effect the supply of fluid under pressure from said mainreservoir to said brake pipe to control the pressure therein,

ii. valve means operative to effect the supply of fluid under pressurefrom said main reservoir to said equalizing reservoir to control thepressure therein, and

iii. fluid pressure operated brake pipe cut-off valve means interposedbetween said relay valve and said brake pipe and operative in responseto the supply of fluid under pressure thereto to cut off flow of fluidunder pressure supplied from said main reservoir to said brake pipe byoperation of said relay valve, Y v e. means operable in response to therate of flow of fluid under pressure from said main reservoir to saidbrake pipe to establish a corresponding pressure differential, whereinthe improvement comprises:

. differential pressure operated means for controlling the supply offluid under pressure to said fluid pressure operated brake pipe cut-offvalve means to cause said cut-off valve means to cut off flow of fluidunder pressure from said main reservoir to said brake pipe, saiddifferential pressure operated means comprising: i. a first valve meansoperable to effect the supply of fluid under pressure from a source offluid under pressure to said pipe cut-off valve means and the subsequentrelease of said fluid under pressure from said brake pipe cut-off valvemeans to atmosphere,

. a movable abutment operably connected to said first valve means foreffecting the operation thereof, the respective opposite sides of saidabutment being subject to fluid under pressure supplied thereto fromsaid brake pipe, and

iii. a second valve means operable by fluid under pressure to controlthe supply of fluid under pressure from said brake pipe to one side ofsaid movable abutment and operable in response to the establishment of achosen differential by said rate of flow responsive means to preventflow of fluid under pressure from said one side of said movable abutmentto said brake pipe to render said movable abutment operative in responseto a reduction of brake pipe pressure on the opposite side thereof tocause said first valve means to supply fluid under pressure from saidsource of fluid under pressure to said fluid pressure oper ated brakepipe cut-off valve means to cause operation thereof to cut off flowoffluid under pressure supplied from said main reservoir to said brakepipe by operation of said relay valve.

2. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized in that said second valve means operable by fluid underpressure comprises a two-position valve, said valve in one of saidpositions establishing two parallel communication from said brake pipeto said one side of said movable abutment, and in the other of saidpositions closing'one of said two parallel communications.

3. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized by volume means connected to said one side of said movableabutment;

4. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized by a one-way flow valve means to provide for flow of fluidunder pressure from said brake pipe to said one side of said movableabutment while said, second fluid pressure operated valve means preventsflow of fluid under pressure from said one side of said movable abutmentto said brake pipe to insure the supply of fluid under pressure to saidone side of said movable abutment notwithstanding operation of saidsecond fluid pressure operated valve means to prevent flow of fluidunder pressure from said one side of said movable abutment to said brakepipe.

5. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized by a one-way flow valve means so interlocked with saidsecond fluid pressure operated valve means as to provide forsimultaneous supply of fluid under pressure from said brake pipe to bothsides of said movable abutment upon an initial increase in the pressurein said brake pipe, while said second valve means prevents flow of fluidunder pressure from said one side of said movable abutment to said brakepipe, to insure operation of said first valve means to cut off thesupply of fluid under pressure from said source of fluid pressure tosaid brake pipe cut-off valve means prior to operation of said secondvalve means to provide for flow of fluid under pressure from said oneside of said movable abutment to said brake pipe.

6. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized in that said second valve means operable by fluid underpressure comprises:

a. a movable abutment subject to the pressure differential establishedby said means operable in response to the flow of fluid under pressurefrom said main reservoir to said brake pipe,

b. a two-position spool-type valve operably connected to said movableabutment and movable by said abutment, upon the establishment of achosen pressure differential by said fluid flow responsive means, from afirst position in which it establishes two parallel communicationsbetween said brake pipe and said one side of said movable abutment thatis operably connected to said first valve means, to a second position inwhich it cuts off flow of fluid under pressure through only one of saidtwo parallel communications, and

c. one-way flow valve means disposed in the other of said two parallelcommunications to provide for flow of fluid under pressure therethroughfrom said brake pipe to said one side of that abutment operablyconnected to said first valve means and prevent flow in the oppositedirection, thereby rendering this abutment operably responsive to areduction of brake pipe pressure on the other side thereof subsequent tothe movement of said spool-type valve to its second position to causesaid first valve means to effect the supply of fluid under pressure fromsaid source of fluid under pressure to said brake pipe cut-off valve andoperably responsive to a subsequent initial increase in the pressure insaid brake pipe, while said spool-type valve remains in its secondposition, to cause said first valve means to cut off the supply of fluidunder pressure from said source of fluid under pressure to'said brakepipe cut-off valve means and release fluid under pressure from saidcut-off valve means to atmosphere.

7. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized in that said brake valve has an emergency valve movablebetween a release position and an emergency position, and said brakecontrol apparatus further comprises:

a. a double check valve device having a delivery port connected to saidbrake pipe cut-off valve of said brake valve and a pair of inlet ports,to one of which said first valve means supplies fluid under pressurefrom said source of fluid under pressure, and

b. a charging cut-off pilot valve device operable in response to anemergency rate of reduction of pressure in said brake pipe to effect thesupply of fluid under pressure from said source of fluid under pressureto the other inlet port of said double check valve device whereby fluidunder pressure is supplied to said brake pipe cut-off valve means bysaid charging cut-off pilot valve device, subsequent to operation ofsaid first valve means to supply fluid under pressure to and thereafterrelease fluid under pressure from said brake pipe cut-off valve means,to maintain said cut-off valve means closed for a chosen length of timeafter the return of said emergency valve to its release positionsubsequent to movement of said emergency valve to its emergency positionfollowing operation of said charging cut-off pilot valve device toeffect the supply of fluid under pressure to said brake pipe cut-offvalve.

8. A locomotive brake control apparatus, as recited in claim 1, furthercharacterized by biasing means disposed on the other side of saidabutment to prevent operation of said first valve means prior to achosen reduction of pressure in said brake pipe effected subsequent tooperation of said second valve means to prevent flow of fluid underpressure from said one side of said abutment to said brake pipe.

9. A locomotive brake control apparatus, as recited in claim 2, furthercharacterized in that said twoposition valve comprises a spool-typevalve having an elongated peripheral annular groove thereon via which,in said one position of said valve, said two parallel communications areestablished, and via which, in said other position of saidvalve, onlyone of said two parallel communications is established.

10. A locomotive brake control apparatus, as recited in claim 4, furthercharacterized in that said one-way flow valve means is disposed betweensaid brake pipe and said second valve means so as to provide for flow inthe direction from said brake pipe to said second valve means.

11. A locomotive brake control apparatus, as recited in claim 6, furthercharacterized by biasing means disposed on one side of said abutment toprevent movement of said two-position spool-type valve by said abutmentprior to establishing on the opposite sides thereof said chosen pressuredifferential.

12. For use in a locomotive brake control apparatus, wherein a brakevalve has a relay valve operative to effect the supply of fluid underpressure from a main reservoir to a brake pipe and a fluid pressureoperated brake pipe cut-off valve means interposed between said relayvalve and said brake pipe and operative in response to the supply offluid under pressure thereto to cut off flow of fluid under pressuresupplied from said main reservoir to said brake pipe, there being ameans, operable in response to the rate of flow of fluid under pressurefrom said main reservoir to said brake pipe to establish a correspondingdifferential, interposed in a conduit connecting said main reservoir tosaid relay valve, wherein the improvement comprises:

a. a differential pressure operated means for controlling the supply offluid under pressure from a source of fluid under pressure to said fluidpressure operated brake pipe cut-off valve means, said differentialpressure operated means comprising:

i. a first valve means operable to effect the supply of fluid underpressure from said source of fluid under pressure to said brake pipecut-ofi' valve means and the subsequent release of said fluid underpressure from said cut-off valve means to atmosphere,

sure from said brake pipe to one side of said movable abutment andoperable in response to the establishment of a chosen differential bysaid rate of flow responsive means to prevent flow of fluid underpressure from said one side of said movable abutment to said brake pipeto render said movable abutment operative in response to a reduction ofbrake pipe pressure on the, opposite side thereof to cause said firstvalve means to effect the supply of fluid under pressure from saidsource of fluid under pressure to said fluid pressure operated brakepipe cut-off valve means to cause operation thereof to cut off flow offluid under pressure supplied from said main reservoir to said brakepipe by operation of said relay valve.

13. A differential pressure operated means, as recited in claim 12,further characterized in that said second valve means operable by fluidunder pressure comprises a two-position valve, said valve in one of saidpositions establishing two parallel communications from said brake pipeto said one side of said movable abutment and in the other of saidpositions closing one of said two parallel communications.

14. A differential pressure operated means, as recited in claim 12,further characterized in that said differential pressure operated meanscomprises a volume means connected to said one side of said movableabutment.

15. A differential pressure operated means, as recited in claim 12,further characterized in that said second valve means operable by fluidunder pressure comprises:

a. a movable abutment subject to the pressure differential establishedby said means operable in response to the flow of fluid under pressurefrom said main reservoir to said brake pipe, and

b. a two-position spool-type valve operably connected to said movableabutment and movable by said abutment, upon the establishment of achosen pressure differential by said fluid flow responsive means, from afirst position, in which it establishes two parallel communicationsthrough which fluid under pressure may be supplied to said one side ofsaid movable abutment operatively connected to said first valve means,to a second position in which it closes only one of said two parallelcommunications.

16. A differential pressure operated means, as recited in claim 12,further characterized by biasing means disposed on the other side ofsaid abutment to prevent operation of said first valve means prior tothe reduction of the pressure of the fluid under pressure effective onsaid other side of said abutment to a chosen value less than thepressure of the fluid under pressure effective on said one side.

17. A differential pressure operated means, as recited in claim 13,further characterized in that said twoposition valve comprises aspool-type valve having an elongated peripheral annular groove thereonvia which,

in said one position of said valve, said two parallel communications areestablished, and via which, in said other position of said valve, onlyone of said two parallel communications is established.

18. A differential pressure operated means, as recited in claim 14,further characterized by biasing means disposed on one side of saidabutment to prevent movement of said two-position spool-type valve bysaid abutment prior to the establishment on the opposite sides thereofof a chosen pressure differential.

19. A differential pressure operated means, as recited in claim 15,further comprising:

a. a first biasing means disposed on the other side of said abutmentoperably connected to said first b. a second biasing means disposed onone side of said abutment operably connected to said spooltype valve toprevent movement of said spool-type valve from its first position to itssecond position by I said abutment prior to the pressure on said oneside exceeding the pressure on the opposite side by a chosen amount.

$31 8? NHTED STATES PATENT omm @ER'HFECATE @F EQTION Patent No.3,749,453 Dated July 31,. 1973 Inventofle) Richard L. Wilson and RobertJ. worbois Ia is certified that error appears in the above-identifiedpatent and that eeid Letters Patent are hereby corrected as shown below:

Column 3, line 51, after "wall" insert --sur*face-'- Column 5, line 49,after "wall" insert --surface-- Column 9, line 11, "chamber" should be--cha.mbers-- line 60, after "have" insert "not-- Signed and sealed this19th day of February 19714..

(SEAL) Attest:

c. MARSHALL DANN EDWARD M.,FLET0HER,JR., commissionerof PatentsAttesting Officer

1. A locomotive brake control apparatus for controlling the brakes on the locomotive and the cars in a train, the combination of: a. normally charged brake pipe, variations of the fluid pressure in which are effective to control brake applications and brake releases on the locomotive and cars, b. a normally charged main reservoir, c. a normally charged equalizing reservoir, d. a brake valve having: i. a relay valve which is subject to the opposing pressures in said equalizing reservoir and said brake pipe and is operative by the differential of the pressures in said equalizing reservoir and in said brake pipe to effect the supply of fluid under pressure from said main reservoir to said brake pipe to control the pressure therEin, ii. valve means operative to effect the supply of fluid under pressure from said main reservoir to said equalizing reservoir to control the pressure therein, and iii. fluid pressure operated brake pipe cut-off valve means interposed between said relay valve and said brake pipe and operative in response to the supply of fluid under pressure thereto to cut off flow of fluid under pressure supplied from said main reservoir to said brake pipe by operation of said relay valve, e. means operable in response to the rate of flow of fluid under pressure from said main reservoir to said brake pipe to establish a corresponding pressure differential, wherein the improvement comprises: f. differential pressure operated means for controlling the supply of fluid under pressure to said fluid pressure operated brake pipe cut-off valve means to cause said cut-off valve means to cut off flow of fluid under pressure from said main reservoir to said brake pipe, said differential pressure operated means comprising: i. a first valve means operable to effect the supply of fluid under pressure from a source of fluid under pressure to said pipe cut-off valve means and the subsequent release of said fluid under pressure from said brake pipe cut-off valve means to atmosphere, ii. a movable abutment operably connected to said first valve means for effecting the operation thereof, the respective opposite sides of said abutment being subject to fluid under pressure supplied thereto from said brake pipe, and iii. a second valve means operable by fluid under pressure to control the supply of fluid under pressure from said brake pipe to one side of said movable abutment and operable in response to the establishment of a chosen differential by said rate of flow responsive means to prevent flow of fluid under pressure from said one side of said movable abutment to said brake pipe to render said movable abutment operative in response to a reduction of brake pipe pressure on the opposite side thereof to cause said first valve means to supply fluid under pressure from said source of fluid under pressure to said fluid pressure operated brake pipe cut-off valve means to cause operation thereof to cut off flow of fluid under pressure supplied from said main reservoir to said brake pipe by operation of said relay valve.
 2. A locomotive brake control apparatus, as recited in claim 1, further characterized in that said second valve means operable by fluid under pressure comprises a two-position valve, said valve in one of said positions establishing two parallel communication from said brake pipe to said one side of said movable abutment, and in the other of said positions closing one of said two parallel communications.
 3. A locomotive brake control apparatus, as recited in claim 1, further characterized by volume means connected to said one side of said movable abutment.
 4. A locomotive brake control apparatus, as recited in claim 1, further characterized by a one-way flow valve means to provide for flow of fluid under pressure from said brake pipe to said one side of said movable abutment while said second fluid pressure operated valve means prevents flow of fluid under pressure from said one side of said movable abutment to said brake pipe to insure the supply of fluid under pressure to said one side of said movable abutment notwithstanding operation of said second fluid pressure operated valve means to prevent flow of fluid under pressure from said one side of said movable abutment to said brake pipe.
 5. A locomotive brake control apparatus, as recited in claim 1, further characterized by a one-way flow valve means so interlocked with said second fluid pressure operated valve means as to provide for simultaneous supply of fluid under pressure from said brake pipe to both sides of said movable abutment upon an initial increase in the pressure in said brake pipe, while said second valve means prevents flow of fluid under pressure from said one side of said movable abutment to said brake pipe, to insure operation of said first valve means to cut off the supply of fluid under pressure from said source of fluid pressure to said brake pipe cut-off valve means prior to operation of said second valve means to provide for flow of fluid under pressure from said one side of said movable abutment to said brake pipe.
 6. A locomotive brake control apparatus, as recited in claim 1, further characterized in that said second valve means operable by fluid under pressure comprises: a. a movable abutment subject to the pressure differential established by said means operable in response to the flow of fluid under pressure from said main reservoir to said brake pipe, b. a two-position spool-type valve operably connected to said movable abutment and movable by said abutment, upon the establishment of a chosen pressure differential by said fluid flow responsive means, from a first position in which it establishes two parallel communications between said brake pipe and said one side of said movable abutment that is operably connected to said first valve means, to a second position in which it cuts off flow of fluid under pressure through only one of said two parallel communications, and c. one-way flow valve means disposed in the other of said two parallel communications to provide for flow of fluid under pressure therethrough from said brake pipe to said one side of that abutment operably connected to said first valve means and prevent flow in the opposite direction, thereby rendering this abutment operably responsive to a reduction of brake pipe pressure on the other side thereof subsequent to the movement of said spool-type valve to its second position to cause said first valve means to effect the supply of fluid under pressure from said source of fluid under pressure to said brake pipe cut-off valve and operably responsive to a subsequent initial increase in the pressure in said brake pipe, while said spool-type valve remains in its second position, to cause said first valve means to cut off the supply of fluid under pressure from said source of fluid under pressure to said brake pipe cut-off valve means and release fluid under pressure from said cut-off valve means to atmosphere.
 7. A locomotive brake control apparatus, as recited in claim 1, further characterized in that said brake valve has an emergency valve movable between a release position and an emergency position, and said brake control apparatus further comprises: a. a double check valve device having a delivery port connected to said brake pipe cut-off valve of said brake valve and a pair of inlet ports, to one of which said first valve means supplies fluid under pressure from said source of fluid under pressure, and b. a charging cut-off pilot valve device operable in response to an emergency rate of reduction of pressure in said brake pipe to effect the supply of fluid under pressure from said source of fluid under pressure to the other inlet port of said double check valve device whereby fluid under pressure is supplied to said brake pipe cut-off valve means by said charging cut-off pilot valve device, subsequent to operation of said first valve means to supply fluid under pressure to and thereafter release fluid under pressure from said brake pipe cut-off valve means, to maintain said cut-off valve means closed for a chosen length of time after the return of said emergency valve to its release position subsequent to movement of said emergency valve to its emergency position following operation of said charging cut-off pilot valve device to effect the supply of fluid under pressure to said brake pipe cut-off valve.
 8. A locomotive brake control apparatus, as recited in claim 1, further characterized by biasing means disposed on the other side of said abutment to prevent operation of said first valve means prior to a chosen reduction of pressure in said brake pipe effected subsequent to operation of said second valve means to prevent flow of fluid under pressure from said one side of said abutment to said brake pipe.
 9. A locomotive brake control apparatus, as recited in claim 2, further characterized in that said two-position valve comprises a spool-type valve having an elongated peripheral annular groove thereon via which, in said one position of said valve, said two parallel communications are established, and via which, in said other position of said valve, only one of said two parallel communications is established.
 10. A locomotive brake control apparatus, as recited in claim 4, further characterized in that said one-way flow valve means is disposed between said brake pipe and said second valve means so as to provide for flow in the direction from said brake pipe to said second valve means.
 11. A locomotive brake control apparatus, as recited in claim 6, further characterized by biasing means disposed on one side of said abutment to prevent movement of said two-position spool-type valve by said abutment prior to establishing on the opposite sides thereof said chosen pressure differential.
 12. For use in a locomotive brake control apparatus, wherein a brake valve has a relay valve operative to effect the supply of fluid under pressure from a main reservoir to a brake pipe and a fluid pressure operated brake pipe cut-off valve means interposed between said relay valve and said brake pipe and operative in response to the supply of fluid under pressure thereto to cut off flow of fluid under pressure supplied from said main reservoir to said brake pipe, there being a means, operable in response to the rate of flow of fluid under pressure from said main reservoir to said brake pipe to establish a corresponding differential, interposed in a conduit connecting said main reservoir to said relay valve, wherein the improvement comprises: a. a differential pressure operated means for controlling the supply of fluid under pressure from a source of fluid under pressure to said fluid pressure operated brake pipe cut-off valve means, said differential pressure operated means comprising: i. a first valve means operable to effect the supply of fluid under pressure from said source of fluid under pressure to said brake pipe cut-off valve means and the subsequent release of said fluid under pressure from said cut-off valve means to atmosphere, ii. a movable abutment operably connected to said first valve means for effecting the operation thereof, the respective opposite sides of said abutment being subject to fluid under pressure supplied thereto from said brake pipe, and iii. a second valve means operable by fluid under pressure to control the supply of fluid under pressure from said brake pipe to one side of said movable abutment and operable in response to the establishment of a chosen differential by said rate of flow responsive means to prevent flow of fluid under pressure from said one side of said movable abutment to said brake pipe to render said movable abutment operative in response to a reduction of brake pipe pressure on the opposite side thereof to cause said first valve means to effect the supply of fluid under pressure from said source of fluid under pressure to said fluid pressure operated brake pipe cut-off valve means to cause operation thereof to cut off flow of fluid under pressure supplied from said main reservoir to said brake pipe by operation of said relay valve.
 13. A differential pressure operated means, as recited in claim 12, further characterized in that said second valve means operable by fluid under pressure comprises a two-position valve, said valve in one of said positions establishing two parallel communications from said brake pipe to said one side of said movable abutment and in the other of said positions closing one of said two parallel communications.
 14. A differential pressure operated means, as recited in claim 12, further characterized in that said differential pressure operated means comprises a volume means connected to said one side of said movable abutment.
 15. A differential pressure operated means, as recited in claim 12, further characterized in that said second valve means operable by fluid under pressure comprises: a. a movable abutment subject to the pressure differential established by said means operable in response to the flow of fluid under pressure from said main reservoir to said brake pipe, and b. a two-position spool-type valve operably connected to said movable abutment and movable by said abutment, upon the establishment of a chosen pressure differential by said fluid flow responsive means, from a first position, in which it establishes two parallel communications through which fluid under pressure may be supplied to said one side of said movable abutment operatively connected to said first valve means, to a second position in which it closes only one of said two parallel communications.
 16. A differential pressure operated means, as recited in claim 12, further characterized by biasing means disposed on the other side of said abutment to prevent operation of said first valve means prior to the reduction of the pressure of the fluid under pressure effective on said other side of said abutment to a chosen value less than the pressure of the fluid under pressure effective on said one side.
 17. A differential pressure operated means, as recited in claim 13, further characterized in that said two-position valve comprises a spool-type valve having an elongated peripheral annular groove thereon via which, in said one position of said valve, said two parallel communications are established, and via which, in said other position of said valve, only one of said two parallel communications is established.
 18. A differential pressure operated means, as recited in claim 14, further characterized by biasing means disposed on one side of said abutment to prevent movement of said two-position spool-type valve by said abutment prior to the establishment on the opposite sides thereof of a chosen pressure differential.
 19. A differential pressure operated means, as recited in claim 15, further comprising: a. a first biasing means disposed on the other side of said abutment operably connected to said first means to prevent operation of said first valve means prior to the reduction of the pressure of fluid under pressure effective on said other side of said abutment to a chosen value less than the pressure of fluid under pressure effective on said one side, and b. a second biasing means disposed on one side of said abutment operably connected to said spool-type valve to prevent movement of said spool-type valve from its first position to its second position by said abutment prior to the pressure on said one side exceeding the pressure on the opposite side by a chosen amount. 